Your Compute Bill Comes Due Before the Invoice Clears

A founder I work with runs an AI-native product at about $7M in run rate. In May he closed the biggest logo he'd ever signed, a three-year deal, and spent the week telling everyone. In June his bank balance was lower than it had been in April, on higher revenue. He thought the bookkeeper had missed something. Nothing was missed. He'd just met the new shape of working capital, and it caught him the way it catches almost everyone building on top of models.

The compute to serve that customer started billing to his card the day they logged in. The customer pays on Net 75.

The cost line stopped waiting

For twenty years, software cost of goods sat quiet at the bottom of the P&L. You built the product once. Serving another customer cost almost nothing, and whatever it did cost showed up slowly, spread across a hosting bill that barely moved month to month. Cash went out for salaries and sales, not for serving.

That's over for anyone with a model in the loop. Every session is inference, and inference gets metered the instant it happens. Your provider charges the card or invoices you Net 15. Meanwhile your enterprise customers negotiated Net 60, Net 75, sometimes Net 90, and they pay on the last legal day. So the money to serve a customer leaves your account roughly two months before the money from that customer arrives. On a flat P&L that spread is invisible. In the bank it's the whole story.

Growth digs the hole faster

Here's the part that traps good operators. The healthier the growth, the deeper the cash dip, because you're always fronting compute on this month's usage while collecting on the smaller usage from a quarter ago.

Run the founder's numbers. That new logo adds around $14K a month in compute the day it turns on, charged as it's consumed. First cash from the account lands 75 days after the first invoice. So he fronts roughly $35K in compute for that one customer before a dollar comes back. Now stack every new account signed that quarter on top. Each one opens its own two-and-a-half-month gap, and they open faster than the old ones close. Revenue climbs, gross margin holds at a respectable 64%, and the balance still falls.

Metered cost of goods turns growth into a cash outflow before it's a cash inflow. The faster you grow, the more compute you pre-fund for revenue you haven't collected. Margin can look perfect while the account drains.

Close the timing, not the margin

The fix isn't cheaper tokens, though cache what you can. It's pulling your cash in to meet the cash going out. Bill annual contracts up front, take a deposit against usage, or move enterprise deals to quarterly-in-advance instead of monthly-in-arrears. Every day you shave off your collection cycle is a day of compute you don't have to bankroll.

Then watch one number: the gap between when you pay to serve and when you get paid to serve. Track it monthly, and size a working capital line to cover it before you need one, not the week you're staring at payroll. The factoring desks already know this gap exists. They're writing facilities against AI receivables right now, and they price the timing risk into every dollar.

Your model provider settles in days. Your customer settles in months. That spread is yours to fund, and it grows every time you win.